The present invention generally pertains to toilet tank flush valve assemblies and is particularly directed to improving the consistency of operation of such assemblies so as to enable better conservation of water.
A typical toilet tank includes a flush pipe having a valve seat for receiving a valve closure element, an upright overflow pipe, and a drain port connecting the overflow pipe to the flush pipe below the valve seat. The valve closure element prevents water from flowing from the tank when the valve closure element is seated on the valve seat.
Typically the valve closure element is a buoyant flapper or ball made of rubber or like material. The flapper or ball type valve closure element is lifted from the valve seat by a chain or rod by operation of a flush lever handle when it is desired to flush the toilet. When the valve closure element is lifted water empties from the toilet tank through the flush pipe. Then, new water enters the toilet tank as the valve closure element is reseated.
When the water empties from the toilet tank through the flush pipe it flows into the toilet bowl. The toilet bowl is flushed of its contents if the pressure created by the water flowing into it from the tank is great enough to cause the water in the bowl to be siphoned therefrom. Accordingly the tank must contain at least a certain quantity of water in order to provide the necessary pressure to initiate the siphoning of the water from the bowl.
However, the bowl usually is flushed by the time that half the water in the tank has emptied therefrom. Yet because the flush valve is open the water continues to empty from the tank and flows into and through the bowl. The bowl is not flushed a second time, however, because the water in the tank has dropped to such a level that it no longer flows into the bowl under sufficient pressure to again cause all of the contents of the bowl to be siphoned therefrom. Thus, the last portion of the water that empties from the tank merely flows through the bowl and down the drain. It is in effect wasted.
Also the water that is wasted includes not only the excess contents of the tank at the time the flush valve is opened, but also the additional water that flows into the tank while the flush valve is open. Typically it takes almost twice as long for the tank to empty after it is only half-full as it did for the tank to drain until it was only half-full.
Attempts have been made to conserve the water remaining in the tank at the time the flushing of the bowl is completed by effecting closure of the flush valve at that time. An example of such an attempt is described in applicant's U.S. Pat. No. 3,350,723 wherein there is described a system where a floating vessel rigidly attached to a ball type valve closure element forces the valve closure element from above to seat on the valve seat when the water level in the tank has receded to a predetermined level above the valve seat. This attempt did not prove satisfactory, however, because the valve closure element did not consistently seat accurately enough on the valve seat to prevent leakage.
Another factor considered in attempting to conserve water is seating of the valve closure element on the valve seat.
As most persons have observed from time to time, the valve closure element in a given flush valve assembly does not reseat as quickly on some occasions as it does on others. This variation in the time for reseating the valve closure element appears to be related to the construction of these typical state of the art flush valve assemblies.
Reseating of the ball, and flapper type valve closure elements is guided by means attached to the valve closure element from above the valve seat. The ball-type valve closure element is guided by a chain or rod which extends from the flush lever above the ball passing through a guide element extended from the overflow tank; and the flapper is guided by being hinged to a location adjacent the valve seat.
Ideally, the ball of flapper valve closure element floats back on the valve seat as the water runs out of the tank and into the flush pipe. However, both the ball and flapper valve closure elements sometimes reseat either early or late in relation to the emptying of the toilet tank.
The reseating of the flapper element is affected by the relative angle to the horizontal that the flapper valve closure element is lifted, and by both horizontal and vertical forces applied against the cocked-open valve closure element by the water flowing from the tank. As a result, if the flapper is not lifted very far, the vertically applied pressure of the outflowing water may cause the flapper to reseat early. If the flapper valve closure element is lifted too far, it may reseat late; and, depending upon its angle and the relative horizontal and vertical pressures of the outflowing water and the new water flowing in to the toilet tank, it may not reseat at all. Also flapper valve closure elements sometimes leak, whereby new water continues to run into the toilet tank.
The reseating of the ball valve element is also affected by how far the ball valve closure element is lifted from the valve seat; and accordingly the ball valve closure element also may reseat early or late.
The reseating of the ball valve closure element is further affected by such factors as corrosion and the forces of usage changing the alignment of the guide element, whereby the ball valve closure element may not accurately reseat and new water continues to run into the toilet tank.
Because of this inconsistency in the time for reseating the flapper or ball valve closure elements, the water level regulating means in many toilet tanks are so adjusted that the toilet tanks receive up to fifty percent more new water upon each refill than is needed for hygienic flushing of the toilet bowl, just so that a sufficient quantity of water flows down the flush pipe from the toilet tank for flushing on those occasions when the valve closure element reseats before the toilet tank is empty.
It is an object of the present invention to provide a flush valve assembly in which the valve closure element is consistently reseated so that only that quantity of water that is needed for hygienic flushing of the toilet bowl is emptied from the tank upon each flushing, whereby water is better conserved.
It is a further object of the present invention to provide a flush valve assembly in which the valve closure element is consistently reseated without leaking so as to prevent water from continuously running into the toilet tank and flowing out through the flush pipe.